Question

Based on published data for a sample of 4 billion people worldwide, 1221 million people have Ascaris, 740 million have hookworms, 795 million have Truchirus, 657 million have filarial worms and 200 million have schistosomes. We survey 150 people from America and record the following parasite loads: 500 people have ascaris, 260 have hookworms, 320 have Truchirus, 300 have filarial worms and 80 have schistosomes. Based on this sample, we want to know if the people of America have about the same parasite frequencies as the worldwide population or if their frequencies are different.

a. Write a null hypothesis to address the question

Answer 1

Null hypothesis: H0: The people of America have about the same parasite frequencies as the worldwide population.

Explanation:

For the given scenario, we have to use the Chi-square test for the goodness-of-fit. The null and alternative hypotheses for this test are given as below:

Null hypothesis: H0: The people of America have about the same parasite frequencies as the worldwide population.

Alternative hypothesis: Ha: The people of America have about the different parasite frequencies as the worldwide population.

In general, the null and alternative hypotheses for this test are given as below:

Null hypothesis: H0: Data follows the given distribution.

Alternative hypothesis: Ha: Data do not follow the given distribution.